Thats easy. No more couple pounds of metal hanging off the mobo. All the CPU heat is exhausted OUT of the case - ignore Corsair's recommendation on air direction its....suboptimal. Easy control over the fan speed/noise profile. As good to better cooling potential. Ease of installation. Ease of swapping ram. Bragging rights. The list does go on and on. ;)

I was hoping that I would hear that the h100i would out perform the D14 by a decent margin. 5C or more would be nice under load.

It would be nice to have a NH D14 or ___________ best air cooler vs the h100i/X60/H220 comparison. Personally I have not touched my D14 for a long long time. It is in my case and it keeps hot things cool. I use ASUS Fan Xpert to manage fan speeds.